To live, for me, Jane, is to stand on a crater-crust which may crack and spue fire any day.
Chapter 20 · Edward Rochester
Context
After Mason has been treated and Jane asks if the danger is past, Rochester explains that his life remains precarious even after Mason leaves England.
Analysis
Rochester's metaphor transforms his entire existence into a geological disaster waiting to happen—he is not on a volcano but is himself the fragile surface, with destruction inherent in his position rather than coming from outside. The active verb 'spue' (an archaic spelling of 'spew') is visceral and almost violent, suggesting eruption as an ugly, uncontrollable expulsion, not a distant possibility but something the ground itself wants to do.
Essay Tip
Use this to argue that Rochester sees himself as constituted by disaster—his identity is the 'crust' barely holding catastrophe in, which explains why he cannot simply confess the truth; revelation would not solve the problem but would be the eruption itself.